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<< Lancair Builders' Mail List >>
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In a message dated 1/1/2002 10:46:41 PM Pacific Standard Time, jschroeder@perigee.net writes:
<<<..Let's keep the snide remarks and insults out of postings that are otherwise
thoughtful...>>>
John:
Your point is well taken. Thanks for the heads-up. Here's my (lame) excuse.
In the world of written communication, I have found that subtlety often results in unclarity. My automatic response to mostly everything is typically laced with some degree of sarcasm. Twisted person that I am, I find it entertaining. I meant no offense to George, who is a noted authority in his field. However, when I see misleading stuff coming from a source having significant credibility, sometimes my keyboard just gets excited.
(BTW, howcum no one gets excited when Marv uses some sarcasm?? REF: (ain't desktop dictionaries great?) <Marv> )
OK, out of time for recreational correspondence, so last input on BMEP:
The following excerpts from prior postings on the subject, in an attempt to debunk the concept of BMEP, really do nothing but obfuscate the fact that BMEP is just another form of "TORQUE PER CUBIC INCH OF DISPLACEMENT". <<<...Because the calculation is done in this manner, it is truly a purely calculated number and does not represent a real world physical event...>>>
<<<...A lot of BMEP in a small displacement engine with a large amount of torque
are "normal". (((I don't really know what that means))) A small amount of stated BMEP with a large amount of stated torque, implies a very large displacement for the engine. (((It doesn't IMPLY that; it CALCULATES it exactly.))) If the engines
all have the same displacement, then different BMEP values for engines of
identical displacements, tells you torque on each engine (((YEP, it's TORQUE PER CUBIC INCH)))...>>>
Bottom line: Torque-per-cubic-inch (BMEP) is a highly useful number for comparing engine operation, and if you know BMEP and displacement, then by simple arithmetic you have brake torque.
If there is any doubt to the above, you can do the algebra yourself and derive it, or you can look in:
C.F.Taylor, "THE INTERNAL COMBUSTION ENGINE IN THEORY AND PRACTICE", Volume 1, Thermodynamics, Fluid Flow, Performance, Second Edition, Apendix 8 (Basic Engine Performance Equations)
where the following relationship is given: MEP = 151 x torque (lb.ft.) / displacement (cu.in.)
or
BMEP = 151 x brake torque per cubic inch of displacement
So a BMEP of 151 means the engine is producing 1 lb-ft of brake torque per cubic inch of displacement. A Lyc IO-540 at 163 BMEP is making 540 x 163/151 (=583) lb-ft of torque, which at 2700 RPM is 300 HP, but at 2400 RPM is only 266 HP. OH, deliver me from these USELESS "..purely calculated numbers which do not represent real world physical events".
(Sorry; couldn't help myself.)
Jack Kane
[Jack, just so you know, my comment about the desktop dictionary
was NOT sarcastic at all, just a statement of the fact of where I got
the definition... I didn't know what it meant either. This just goes to
show you how easy it is to have one's INTENT misunderstood when using
this particular format. That being said, my only recommendation is
to always read through what you're sending one last time before
hitting that SEND button, just to be sure that you're not saying something
to someone that you wouldn't mind having someone say to you. This
suggestion is not aimed at anyone in particular, just a tidbit of guidance from someone who's been actively involved in online communications
for the past 20 years. Happy new year.
<Marv> ]
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